package basic;

/**
 * @Author: 海琳琦
 * @Date: 2021/8/31 9:15
 */
public class Title21 {
    static class ListNode {
        int val;
        ListNode next;
        ListNode() {}
        ListNode(int val) { this.val = val; }
        ListNode(int val, ListNode next) { this.val = val; this.next = next; }
    }

    public static void main(String[] args) {

    }

    private static ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode head = new ListNode(-1);
        ListNode pre = head;
        while(l1!=null&&l2!=null){
            if(l1.val<=l2.val){
                pre.next = l1;
                l1 = l1.next;
            }else{
                pre.next = l2;
                l2 = l2.next;
            }
            pre = pre.next;
        }
        pre.next=l2==null?l1:l2;
        return head.next;
    }

}
